Wheel chairs are generally driven by the user grasping a push ring which is attached to the periphery of the supportive wheels. This is not adequate for the user who lacks sufficient arm strength or full control and use of her or his hands and arms. Several devices have been put forth to address this problem. A brief discussion of a representative sampling of these devices is set forth below.
U.S. Pat. No. 3,877,725 to Barroza describes a handle which is grasped by the user and pivots from the axle of the wheel. In this device, the user would advance the handle forward to a suitable distance forward on the wheel, and a clamp would grasp the push ring thereby advancing the chair forward.
U.S. Pat. No. 4,538,826 to Lemarie describes another axle mounted device in the form of a caliper assembly which fits over the axle and terminates in a handle for actuation by the user.
U.S. Pat. No. 3,869,146 to Bulmer sets forth another axle-mounted single handle device comprising a lever or handle extending outwardly from the axle to the handle. This device is formed to grip a push ring of a large wheel upon a propulsion stroke and to release its grip of the ring upon the return stroke.
Other devices, all of which comprise a single handle radiating from and pivoting from the axle of the main wheel, are found in U.S. Pat. No. 6,634,663 to Mitchell, U.S. Pat. No. 4,354,691 to Saunders and Lowe, and U.S. Pat. No. 3,189,368 to Petersen.
All of these devices have only one point of contact with the wheel push ring and are wheel axle pivoted with complex mechanical grips between the device and the wheel. None of the above cited references describe the secant configured device of the present invention. The secant configuration loosely grips the wheelchair push ring in two places instead of one, thereby lending stability and a mechanical advantage over the devices of the prior art. Also, since the device of the present invention does not attach at the axle, it eliminates the need for significant chair modification and eliminates additional stress to the axle that is present in prior art devices.